CINCINNATI — Catholic peace activists, including an 85-year-old nun, who painted slogans and splashed blood on a Tennessee bunker storing much of this country's bomb-grade uranium want an appeals court to overturn their sabotage convictions.

At the 6th U.S. Circuit Court of Appeals on Thursday, attorney Marc Shapiro argued that trespassing and property destruction charges could have been justified, but sabotage was an overreach.

At issue is whether the activists' July 28, 2012, nonviolent protest injured the national defense by disrupting operations at the Y-12 National Security Complex in Oak Ridge, Tennessee.

Sister Megan Rice, 66-year-old Michael Walli and 59-year-old Greg Boertje-Obed (bohr-CHEE' OH'-bed) were able to cut through several fences and reach a high security area where they hung banners, prayed and hammered on the outside wall of the bunker to symbolize a Bible passage that refers to the end of war: "They will beat their swords into ploughshares."

In court, Shapiro likened the activists' case to a government overreach case ruling last month in the Supreme Court. Justices said a fisherman who dumped undersized grouper was wrongfully prosecuted for destroying evidence under a law targeting accounting fraud passed in the wake of the Enron scandal.

Shapiro also cited a 2014 case where the Supreme Court ruled a Pennsylvania woman who tried to poison her husband's mistress should not have been charged with using a chemical weapon.

Judge Raymond Kethledge questioned Assistant U.S. Attorney Jeff Theodore, "Isn't this just as far-fetched? Aren't the ramifications just as sweeping, if we don't step back from an interpretation of the national defense that is so eggshell that hanging banners constitutes an act of sabotage?"

"I don't think you have the same concern here," Theodore said. "The national defense has broad connotations, and Y-12 is absolutely crucial to the national defense."

Theodore also referred to the protesters' many statements that they were seeking nuclear disarmament.

"These are people who have a desire, an intent, to disarm, and they are taking action in furtherance of that goal," he said.

Shapiro argued that disarmament may have been the activists' aspiration, but there was no way they could have accomplished it with their actions at Y-12. It could only be achieved "through a groundswell of support over many years."

About 25 supporters of the activists were in the gallery for the hearing, including several fellow peace activists who had been involved in similar protests, collectively known as ploughshares actions.

Liz McAlister, a former nun who spent three years in prison for hammering on a B-52 bomber, said in an interview after the hearing that ploughshares actions are meant to be symbolic. They don't actually try to destroy bombs or missiles because they know the government will just replace them, she said.

"The idea is to change minds and hearts, and to do so by risking your own freedom and, in some cases, life and limb with what you do."

Rice is serving a sentence of just under three years for the action, while Walli and Boertje-Obed are each serving sentences of just over five years.